On Apr. 12, 1981, a new era in space flight began as the first reusable space shuttle embarked on its first voyage into space. The plane-like element of the space shuttle is the orbiter that carries the crew and payloads. The payloads may include an object such as a satellite that is to be ejected from the payload bay of the orbiter while in flight.
The apparatus for ejecting these objects from the payload bay of the orbiter obtained their motive force from a compressed spring or springs that eject the object with relative low velocity. The objects in the payload bay were retained before release by a retention mechanism which included a clamp, which clamp was cut to release the spring. For those satellites and probes that are spin stabilized, the entire apparatus including the spring was rotated.